1. Field of the Invention
This invention relates to a duplexer, comprising; a media input nip, an auxiliary roller nip located downstream of the media input nip such that the auxiliary roller nip comprises an auxiliary drive roller that exhibits slippage so that the auxiliary roller nip maintains constant contact with a sheet of media to be duplexed, a backstop located downstream from the auxiliary roller nip, and a media output nip located adjacent to the auxiliary roller nip.
2. Description of the Related Art
Prior to the present invention, as set forth in general terms above and more specifically below, it is known, in the duplexing art that printing on two sides of the media is achieved by a duplexer that ejects the media from the print engine, after printing on side one, into a duplex tray where the media is stopped by a backstop. This media tray jogs the media against one side and a roller nip closes on the new leading edge of the media, reverses the direction of travel of the media, and sends the media back to the print engine where the printing of the second side of the media can be completed. While this system is capable of duplexing media, this design depends upon consistency of the cut sheets of media. However, it is well known that the sheets of media are not always cut consistently and the side one/side two image placement may not match. Consequently, a more advantageous system, then, would be provided if the duplexing the device could provide a more accurate side one/side two image placement regardless of the type of media.
It is also known, in the duplexing art, to employ a variety of rollers that are utilized to place images on both sides of the media. Exemplary of such prior art is a duplexing device that uses rollers to grab the leading and trailing edges of the sheet of media. While these devices are also capable of duplexing the media, these devices do not constantly retain the media. Consequently, registration between the side one and side two images can be adversely affected. Alternatively, the devices may constantly retain the media, but they utilize complex electronics, sensors, motors, and controllers to coordinate the various rollers. Therefore, a further advantageous system, then, would be provided if the media were constantly retained within the duplexing device without additional control electronics, firmware, motors, or sensors.
It is apparent from the above that there exists a need in the art for the duplexing device that is able to provide a more accurate side one/side two image placement regardless of the type of media, and which at the same time it is capable of constantly retaining the media within the duplexing device. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.